Cancelling integrity check prevents "Welcome!" screen on serial console

[dann frazier]

20200730 20.04.1 RC live-server ISO on an arm64 (Marvell/Sabre) server, Install mode.

When I let the ISO boot uninterrupted, I end up with a "Welcome!" screen on both the serial console and the graphical head. The serial console screen gives me "Switch to rich mode", "View ssh instructions", and "Continue in basic mode" options.

However, if I ^C the integrity check - this screen never appears. The last thing I see is:

-----END SSH HOST KEY KEYS-----
[ 1844.876737] cloud-init[4630]: Cloud-init v. 20.2-45-g5f7825e2-0ubuntu1~20.04.
1 running 'modules:final' at Fri, 31 Jul 2020 00:34:37 +0000. Up 1844.50 seconds
.
[ 1844.900161] cloud-init[4630]: ci-info: no authorized SSH keys fingerprints fo
und for user installer.
[ 1844.916172] cloud-init[4630]: Cloud-init v. 20.2-45-g5f7825e2-0ubuntu1~20.04.
1 finished at Fri, 31 Jul 2020 00:34:37 +0000. Datasource DataSourceNoCloud [see
d=/var/lib/cloud/seed/nocloud][dsmode=net]. Up 1844.86 seconds
[ 1844.944217] cloud-init[4630]: Welcome to Ubuntu Server Installer!
[ 1844.964137] cloud-init[4630]: Above you will find SSH host keys and a random
password set for the `installer` user. You can use these credentials to ssh-in a
nd complete the installation. If you provided SSH keys in the cloud-init datasou
rce, they were also provisioned to the installer user.
[ 1844.996149] cloud-init[4630]: If you have access to the graphical console, like TTY1 or HMC ASCII terminal you can complete the installation there too.

A Welcome! screen does appear on the graphical head, and I can ssh in to get an installer - but I have no serial install option.